Lambda Expressions - Java 8 Recipes - page 219

public class MainClass {
public static void main(String[] args){
double x = 16.0;
double y = 30.0;
double z = 4.0;
// Create volume calculation function using
a lambda. The calculator
// checks to ensure that the array contains the
three necessary elements
// for the calculation.
Function<List<Double>, Double> volumeCalc = list
-> {
if(list.size() == 3){
return list.get(0) * list.get(1)
* list.get(2);
} else {
return Double.valueOf("-1");
}
};
Double[] argList = new Double[3];
argList[0] = x;
argList[1] = y;
argList[2] = z;
// Create area calculation function using
a lambda. This particular
// calculator checks to ensure that the array
only contains two elements.
Function<List<Double>, Double> areaCalc = list ->
{
if(list.size() == 2){
return list.get(0) * list.get(1);
} else {
return Double.valueOf("-1");
}
};